I'm trying to build a digital clock using ESP32. I cannot use the TM1637 display module because it's too small. So I'm using a generic common anode 4 digit 7 segment display. I used the Arduino SevSeg library on ESP32 and it worked perfectly. However, it consumed a lot of GPIO pins. Hence I used two 74HC595 registers and connected them exactly as described in the SevSegShift library (a fork of SevSeg library but with shift registers), like this: Circuit diagram
Unfortunately, when I run the code, I get wrong output. No matter what number or characters I try to display, only the "b" segment of the corresponding digits are turned on, all other segments of all digits are turned off. For ex, if I try to display "1111", only the "b" segment of all digits are turned on, rest all segments of all digits are turned off. As a result only upper half of "1111" is displayed on the 7 segment display, like this:
Here's the code:
#include <Arduino.h>
#include <SevSegShift.h>
#define SHIFT_PIN_DS 5 /* Data input PIN */
#define SHIFT_PIN_STCP 19 /* Shift Register Storage PIN */
#define SHIFT_PIN_SHCP 18 /* Shift Register Shift PIN */
SevSegShift sevseg(SHIFT_PIN_DS, SHIFT_PIN_SHCP, SHIFT_PIN_STCP); //Instantiate a seven segment controller object (with Shift Register functionality)
void setup() {
// put your setup code here, to run once:
byte numDigits = 4;
byte digitPins[] = {8+2, 8+5, 8+6, 2}; // of ShiftRegister(s) | 8+x (2nd Register)
byte segmentPins[] = {8+3, 8+7, 4, 6, 7, 8+4, 3, 5}; // of Shiftregister(s) | 8+x (2nd Register)
bool resistorsOnSegments = false;
byte hardwareConfig = COMMON_ANODE;
bool updateWithDelays = false;
bool leadingZeros = false;
bool disableDecPoint = false;
sevseg.begin(hardwareConfig, numDigits, digitPins, segmentPins, resistorsOnSegments, updateWithDelays, leadingZeros, disableDecPoint);
}
void loop() {
// put your main code here, to run repeatedly:
sevseg.setNumber(1111, 0);
sevseg.refreshDisplay();
delay(1);
}
What am I doing wrong? Is the circuit layout given above correct? More importantly, does the SevSegShift library work with ESP32?
), get one or more (more, of course, buy half a dozen!) of the matrix module kits from Aliexpress and use the convenient PCB with the MAX7219 mounted; ignore the matrix display and the socket pins for it, connect your display.
